The manual insertion of tubes arranged inside the casings is known today in production and manufacturing lines for producing artificial casings to favor the removal and ventilation of fluids present inside them during their passage through the drying phase (dryer). However, in subsequent phases of the production line, said tubes entail some drawbacks, among which the following stand out:                If the casing is wound on a reel without previously removing the tubes, lumps are formed inside the reel on which successive layers of casing are tightened. This causes deformations of the contacting layers, which often requires discarding them to prevent anomalous behavior of the casing during its subsequent shirring or filling phase. As it is a point of interruption of the process, it can be a weak point where the casing breaks.        The reel of smooth casing can have several tubes therein from the cyclical cuts for draining, or from additional cuts made manually, for example if an additional removal of trapped liquids/gases is necessary, or to restore the continuity of a break of the casing in the process, or to inflate the trapped air pocket in the dryer as it gradually loses air pressure. Some examples of the use of these tubes in artificial casings can be found in the following documents: U.S. Pat. No. 3,247,037 (“Puncture seal”); U.S. Pat. No. 3,799,823 (“Method for splicing collagen casing”); U.S. Pat. No. 3,917,862 (“Method for patching edible artificial collagen sausage casings”); U.S. Pat. No. 6,004,488 (“Continuous process for the manufacture of tubular food casings”).        Although the tubes can be discarded on the reel, for example by starting a new reel every time a tube arrives, this manner of proceeding is rather inefficient, slow and tedious, generating “downtimes”.        The tube can be a bother in the subsequent processing of the smooth casing: For example, if the smooth casing is subjected to a printing process, for which purpose it goes between high speed printing rollers, when the tube arrives it hits against the rollers and the casing breaks as a consequence, the tube gets stuck, and the printing system must be threaded up again and re-launched, the rollers cleaned, etc. Likewise, if the smooth casing is subjected to a shirring process, the smooth casing can be fed by pulling between pressed rollers at a high speed. When the tube arrives it also hits against the rollers and the casing breaks as a consequence, the tube gets stuck, and the shirring system must be threaded up again and re-launched, etc.        If the tube successfully passes between the rollers, the smooth casing is threaded on a spindle. The tube can hit against the spindle and the shirring stops. This has the drawback of having to remove the tube and threading up the entire system again.        The half-finished shirred stick must be removed, thereby wasting valuable material which represents a considerable loss when multiplied by the large amount of sticks obtained daily.        One possible way of avoiding the aforementioned situation is for the operator himself/herself to manually cut the tube once he/she visually detects its arrival, discarding the piece of casing which contains said tube, and subsequently winding the casing on the reel again. The main problem with acting in this manner is that the winding reel sustains interruptions which accordingly cause the subsequent shirring process to be stopped. Furthermore, the considerable drawback involved in having to have an operator who is at all times aware and attentive with respect to this phase of the production line after the exit of the casing from the dryer with the tubes included must be pointed out, with the possible human errors or faults that may occur, being a task which requires concentration, constant attention and time, not to mention the stress that this generates for the operator.        
Therefore, the presence of tubes after the drying phase entails deformations on the winding reel, which leads to interruptions in the shirring machine, and accordingly to a substantial loss in production line productivity, where machine stops and “downtimes” translate into very significant economic losses.